<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box {
            width: 1000px;
            height: 500px;
            border: 5px solid green;
            background: url("img/gamepic10.jpg"),
                        url("./img/gamepic2.jpg") , 
                        url("img/gamepic9.jpg");
            /* 分别设置 */
            background-repeat: no-repeat;
            background-position: 0 0, 500px 300px, center;
            background-size: 300px 300px,500px 500px,cover;
        }
    </style>
</head>
<body>
    <div class="box"></div>
</body>
</html>